1. Field of the Invention
The present invention relates to a gas compressor.
2. Description of Related Art
A vehicle such as an automobile includes an air conditioner which adjusts the temperature in a vehicle interior.
Such an air conditioner includes a refrigerant cycle which circulates a refrigerant (cooling medium) in order of a gas compressor, condenser, expansion valve, and evaporator.
The gas compressor in the refrigerant cycle is configured to compress the refrigerant gas with the evaporator, and send the high-temperature and high-pressure refrigerant gas to the condenser.
Such a gas compressor includes a vane rotary compressor (refer to, for example, JP 554-28008A).
The vane rotary compressor includes a hollow cylinder member, a rotor rotatably disposed inside the cylinder member, and a plurality of vanes which is attached to the rotor in a projectable and houseable manner, the vanes having leading ends which have contact with an inner circumferential surface of the cylinder member, so as to form a plurality of compression rooms inside the cylinder member.
A cylinder room which performs a refrigerant gas compression cycle by changing the volume of a compression room is formed between the cylinder member and the rotor. A suction section capable of sucking the refrigerant gas is provided upstream of the cylinder room, and a discharge section capable of discharging the refrigerant gas is provided downstream of the cylinder room.
However, the gas compressor has the following problems.
That is, the efficiency (COP (Coefficient of Performance: Cooling Capacity/Power)) of the vane rotary compressor tends to decrease compared to a compressor of another type.
This is because of the following reasons.
Namely,
1. The vane rotary compressor rapidly compresses refrigerant gas. For this reason, the refrigerant gas is excessively compressed, so that the power loss is increased due to the excessive compression.
2. The vane rotary compressor rapidly compresses refrigerant gas. For this reason, a pressure difference between adjacent compression chambers is increased, so that the refrigerant gas easily leaks from the vane by the compression difference.
This is especially a problem during high-load driving. This problem occurs not only in a case when a target to be compressed by the above compressor is refrigerant gas but also in a case when a target to be compressed by the above compressor is general gas.